Spring hammer



Dec. 9, 1924.

A. T. PRESCOTT S PRING HAMMER Filed July 30, 1920 AJR Hl/R IPRISCOU /i 61mm Patented Dec. 9, 1924.

UNITED STATES PATENT OFFICE.

ARTHUR T. PRESCOTT, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO J. EDWARD OGDEN, 0F MOUNTAINVILLE, NEW YORK.

Application led July. 30,

` To all whom t may concern Be it known that I, ARTHUR T. PREsoo'r'r, a citizen of the United States, and a resident of East Orange, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Spring Hammers, of which the following is a specilication, reference being had to the accompanying drawing, forming a part thereof.

My invention relates to spring hammers of the type particularly used in drilling stone,.brick 'and concrete, and the main object is to provide means whereby a more forcible power blow may be applied upon the drill simultaneously during the drilling process.

I accomplish this in the combination of a main spring under a light compression with an auxiliary spring which may be compressed by the operator, the main spring being -for-the purpose of delivering a nor` mal striking blow upon the drill during its drilling process, and the auxiliary spring is to provide a compressive but yielding action under pressure when the operator bears upon the breast plate, compressing the main spring and increasing the effect of the power blow upon the drill.

My invention comprises various features of construction as hereinafterdescribed in the following specification and pointed out in the appended claims, and illustrated by the accompanying drawing, in which:

Figure `1 is a. longitudinal section of a hammer which is made according to and embodies this invention. y,

Figure 2 is a plan-view of the same.

Figure 3 is ay cross-section ofthe hammer on line 3 3, Fig. 1.

Figure 4 is a fragmentary sectional view. illustrating the parts ready to deliver a striking blow upon the drill. e A

Figure 5 is a cross-section of the hammer on line 5-5, Fig. 4. y

Like characters of reference designate corresponding parts.

1 lindicates a breast plate secured upon a bushing 2 which is adjustably Vmounted on a tubular barrel 3 as by a threaded portion 4 and secured thereon by a pin 5, A ymain p on each side.

the casing SPRING HAMMER.

1920. Serial No. 400,035.

' ing 12 and a left casing 13, both of which are clamped together by screws 14, which have holes in their ends for spreading and locking them. The barrel 3 is slidablc through the split housing and also slidable within a socket member 15 provided with a gear 16, which meshe'swith a pinion 17 on a shaft 18.

A spiral gear 19 on the shaft 18 meshes with a similar gear 2O on the shaft 21 onto which is secured the cam wheel 9, as by a left hand threaded portion 22. The shaft 13 is provided with a reduced end portion 23 which is mounted in a bearing portion 24 of the casing 12. A crank handle 33 is aHiXed to the other end of this shaft.

The striker 7 is held in alinement with the cam wheel 9 a screw 25 with its head 26 within a slot 27 of the striker 7. The

. screw extends also into a slot 29 formed by the casings 12 and 13. The barrel is held in tension by an auxiliary spring 30 and stop pins 31 secured to the casings 12 and 13 and engaging slots 32 in the barrel 3, two slots These pins 31 act also as guidesl to the slidable barrel 3 in order to keep it from rotating, cranking of handle 33 in a plane approximately at a right angle to the breast plate 1.

A grip or holding handle 35 `is secured to 12 for the operator to hold the hammerl and a hole 36 in the bushing 2 is for inserting a bar instead of the breast plate, when desired.

The compression of the main spring 6 may be adjusted by rotating the bushing 2 after first removing the pin 5. The barrel 3 is provided with a slot 40 through which the cam wheel 94rotates, and a rubber washer or ring 41 is inserted onto the chuck 15 for preventing the spray of dust from the so as to have the H drilling getting into the housing. The drill bit 42 may be of any desired size, shape and material and is held in the socket member by a square hole 48.

In operation: rllhe breast plate 1 is placed upon the breast of the operator and the drill bit upon the work W7 which is to be drilled, (Figure 4). rThe operator then turns the crank handle 33 which through the 16, 17, 19 and 2O rotates the chuck l5 and the drill bit 42, and at the same time the cam wheel 9 rotates, so that its teeth 10 successively engage the shoulder 11 at one end of the slot 8, thereby compressing the main spring 6 to .produce a desired `oower strore. f,As the teeth 10 pass the shoulder 11, the compression of the spring 6 shoots the striker 7 so it strikes the chuck stein 44 of `thedrill bit 42. rlhis produces very rapid tappet action upon the drill bit and the gearing heretofore described rotates the drill bit. The auxiliary spring 3() bears between the end of the bore of the socket member 15 and upon the end 51 of the barrel 3.

ln light drilling with small bits, the action of the main spring 6 is suilicient. But where hard yand heavier drilling is done, a more forcible power stroke is recpiired.v ln this case,` the operator bears upon the/breast plate 1., and compresses the auXiliary spring 30, and 'this increases the compression of the main spring 6. The spring '6 thus ldelivers a variable power stroke upon the drill bit, Adepending upon the pressure the op` erator may bear upon the breast plate 1.

Y It is to be understood that l: may use other means than those shown to accomplish thesame operative results, withoutV departing from the spirit and scope of this invention and I intend no limitations other than those imposed by the appended claims.

What l claimis:

1. A. spring hammer comprising abreast plate, abit holding device, spring actuated :mechanism for imparting blows to a bit, saidl mechanism including a spring and spring compressing and releasing means,

,and resilientmeans intermediate the breast plate and bit for transmitting to the bit pressure on the breast plate.

2. A. spring hammer comprising a breast plate, a bit holding device, spring pro- --pelled plunger for delivering blows upon a bit and lmeans including a spring and springr compressing and releasing' means for actuating the plunger, and an auxiliary spring intermediate the breast plate and bit andarranged to increase the pressure of the bit onthework as pressure on the breast "plate is increased.

3. Ajspring hammer comprising a pres- Ysure plate, a bit holding device, a plunger,

yagspringl arranged to force the plunger against a bit, actuating mechanism cooperating With said spring to compress. and repression spring within one end of said tubu-y lar barrel, an auxiliary spring at the other end of said barrel, a bit holding device adjacent said auxiliary spring, means for actuating said cam wheel to compress and release said main spring to impart'blows upon a bit, Aand means for compressingsaid auxiliary spring to increase the blows upon the bit..

y5. A spring hammer, comprising a split casing, a tubular barrel slidable therethrough, a cam wheel within said housing, a reciprocatory plunger and a main .com-

pression spring within one end of said tubular barrel, an auxiliary spring at the other end of said barrel, said auxiliary spring bearing upon a bit holding device and upon the end of said barrel, means forV actuating said cam wheel to compress ,and re! lease the main spring to vimpart blows upon a bit, and means for compressing said auxiliary spring to increase the compression of the main spring whereby the effect of said blows is increased. l Y

dei. spring hammer, comprising split housing, a tubular barrel slidable. therethrough, a breast plate adiustably` secured to one end of said barrel, a reciprocating plunger' within said barrel, a main spring interposin'g between the breast plat-eA and plunger, a bit holding device upon the other end of the barrel slidable within said housing, an ausili ary spring interposing between the bit hol'dingdevice and the adjacent end ofthe barrel, a cam wheel in said casing, means for actuating the cam wheel to` coinpress and release `the main spring to cause the plunger to impart intermittent striking blows upon a bit, and means controllable at the will of the operator for forcing the barrel into the bitJH holding device to come press said auxiliary spring to force the bit againstthe work and to increase vthe coin pression of the mainspring. f

7. A. spring hammer, comprising afsplit housing, a tubular barrel slidable there through, a breast plate adjustably secured to one end of said barrel, a .reciprocating plunger within said barrel, va imain spring interposing between the breast plate 'and plunger, a bit holding device uponthe yother end of the barrel slidable and y,rotatable within said housing, an auxiliary spring interposing between the bit holding device and the adjacent end of the barrel, a cam wheel in said casing, means for actuating the cam Wheel to compress and release the main spring to canse the plunger to impart intermittent striking blows upon a bit,

' means controlled by the rotation of said cam for rotating the bit holding device, and means controllable at the will of the operator for forcing the barrel into the bit holding device to compress said auxiliary spring to Ytorce tlie bit against the Work and to increase tbe compression of the main spring. n Witness whereof, l have hereunto set my hand this 22nd day of July, 1920.

ARTHUR T. PRESCOTT. 

